BC6364 – Toyota 2GRFE – ProH625+ Connecting Rods w/ARP Custom Age 625+ Fasteners

For the engineer and builder who views the Toyota 2GR-FE not as a mere powerplant but as a kinetic sculpture of unrealized potential, the BC6364 ProH625+ Connecting Rods represent the definitive structural upgrade. This is not a component for casual modification; it is a foundational re-engineering of the engine’s reciprocating assembly, designed to transform the robust 2GR into a platform capable of withstanding the extreme cylinder pressures and inertial forces generated by significant forced induction or high-RPM aspiration. Brian Crower’s BC6364 kit, featuring its proprietary ProH625+ forgings mated to ARP Custom Age 625+ fasteners, is engineered to a single standard: absolute reliability under duress. It bridges the critical gap between the factory rod’s inherent limitations and the demands of 600+ wheel horsepower applications, providing the deterministic strength required to execute aggressive performance builds with confidence. Every dimension, tolerance, and material specification is optimized to serve this singular purpose, making it the non-negotiable core of any serious 2GR-FE performance transformation.

Material Science & Forging Integrity: The ProH625+ Foundation

The defining characteristic of the BC6364 rod set is its construction from premium 4340 chromoly steel, processed under the proprietary ProH625+ specification. This denotes a material and manufacturing pedigree far beyond standard 4340 offerings. The “H” signifies a vacuum degassed, electric furnace melted alloy, ensuring exceptional purity and homogeneity by removing dissolved gases and non-metallic inclusions that could become stress concentration points. The “625+” refers to the final ultimate tensile strength exceeding 625,000 PSI, a figure achieved through a meticulously controlled heat-treating and quenching process. This results in a connecting rod with an optimal balance of yield strength, fatigue resistance, and controlled elasticity. The forging process itself, performed under immense pressure, aligns the steel’s grain structure to follow the rod’s complex contours, creating a part that is stronger and more durable than any machined-from-billet alternative. This material foundation is why the ProH625+ rod can reliably handle the violent, repetitive loading cycles that would cause lesser components to yield or fail catastrophically.

Precision Engineering & Critical Design Features

Beyond the raw material, the BC6364 is defined by a suite of precision-machined features that ensure perfect integration and longevity within the 2GR-FE’s rotating assembly. Each rod is weight-matched to within a 1-gram tolerance set, a critical step for achieving smooth engine operation at elevated RPMs, minimizing destructive harmonic vibrations. The small end is precision honed to the exact specification for a press-fit piston pin, providing a secure, zero-play interface that maximizes heat transfer from the piston. The large end incorporates a fracture-cap design. This manufacturing technique involves creating a intentional, laser-etched stress point on the rod cap. When the cap is separated, it breaks along this perfectly mated surface, resulting in an unparalleled cap-to-rod alignment that cannot be replicated by traditional machining methods. This ensures perfect bearing crush and oil clearance consistency. Furthermore, all stress-critical radii are extensively rolled and polished, eliminating microscopic tooling marks that can initiate fatigue cracks, thereby extending the component’s service life exponentially under high-load conditions.

Uncompromised Fastener Technology: ARP Custom Age 625+

Brian Crower’s decision to equip the BC6364 with ARP 2000 3/8″ fasteners as standard, with an upgrade path to ARP Custom Age 625+ bolts, is a testament to a systems-engineering approach. The connecting rod is only as strong as its weakest point, which is invariably the fastener clamping the cap to the rod body. The included ARP2000 fasteners are already a significant upgrade, but the optional 625+ fasteners represent the pinnacle of metallurgy for this application. Manufactured from a proprietary nickel-chromium-molybdenum alloy, they are solution treated and aged to achieve a tensile strength of over 260,000 psi and a yield strength exceeding 230,000 psi. Most critically, they exhibit exceptional fatigue resistance and resistance to stress relaxation—the tendency of a bolt to lose clamp load over time under extreme heat and vibration. This ensures the rod bearing remains precisely located and lubricated, preventing the spin failures that plague overtaxed engines. For a comprehensive technical analysis of fastener metallurgy, consult this authoritative resource on high-performance engine fasteners.

• ProH625+ 4340 Chromoly Material: Provides ultimate tensile strength exceeding 625,000 PSI for maximum durability under boost and high RPM.
• Weight-Matched & Balanced: Each set is balanced to within 1 gram, ensuring smooth operation and reducing harmonic vibrations at elevated engine speeds.
• Fracture-Cap Design: Guarantees perfect cap-to-rod alignment for optimal bearing fit, oil clearance, and overall strength.
• Premium ARP Fasteners: Features high-clamp, high-fatigue ARP 2000 bolts standard, with an upgrade to the top-tier ARP Custom Age 625+ fasteners available.
• Direct OEM Replacement Dimensions: Maintains stock center-to-center length, rod journal diameter, and pin diameter for drop-in fitment with appropriate pistons.
• Fully Machined & Finished: Includes shot-peened and stress-relieved surfaces with polished radii to combat fatigue and micro-cracking.

Vehicle Fitment & Application Specifics

The BC6364 kit is engineered as a direct, dimensionally accurate replacement for the factory Toyota 2GR-FE connecting rods. It maintains the stock center-to-center length, ensuring correct piston deck height and compression ratio when paired with compatible aftermarket pistons. This rod is the cornerstone for builds targeting reliable power levels well beyond the factory block’s safe limit. Its primary application is in forced-induction (turbocharger or supercharger) builds, high-compression naturally aspirated race engines, and any application where the engine will see sustained operation above 7,000 RPM. It is compatible with all generations of the 2GR-FE, 2GR-FSE, and related variants found in a broad range of Toyota and Lexus vehicles.

Vehicle Fitment: Toyota Avalon (2005+), Toyota Camry/V6 (2007+), Toyota Highlander/V6 (2008+), Toyota RAV4/V6 (2006+), Toyota Sienna (2004+), Lexus ES 350 (2007+), Lexus GS 350 (2007+), Lexus IS 350 (2006+), Lexus RX 350 (2007+), Toyota Tacoma/V6 (2005+), Lotus Evora, Lotus Exige S/Emira, among others equipped with the 2GR-FE/FSE engine.

Technical Specifications & Installation Considerations

Installation Note: Proper installation is paramount. These rods require precise measurement of the rod journal bore for correct bearing selection and final assembly with a torque wrench calibrated to ARP’s specifications, using their recommended lubricant. The piston pin bore is designed for a press-fit; professional installation with the correct tooling is mandatory to avoid damaging the rod small end. This component is intended for use with performance pistons and a fully balanced rotating assembly. Always verify clearances (piston-to-wall, rod bearing, main bearing) during assembly.